The invention relates to transport trolleys used for transporting loads and which can be converted in order to be stored or stowed, if necessary with their load(s).
Here “transport trolley” is understood to be a convertible system (or device), comprising a pair of approximately parallel legs, which can be rolled when pushed or pulled and is capable of supporting at least one load. Consequently, it could involve for instance a two-wheeled trolley, a shopping cart, a stroller or a modular element of a platform floor of a vehicle.
On the other hand, in the following, the word “load” designates any heavy body, no matter whether it is a person (baby, infant or adult), animal, vegetable or object.
A person skilled in the art knows that some transport trolleys of the aforementioned type comprise, on the one hand, a pair of legs with lower extremities to which are coupled respectively plates on which wheels are mounted in rotation in a transverse direction, and on the other hand, load support means which are coupled to the lower extremities of the legs.
Several solutions have been proposed in order to reduce the space occupied by these transport trolleys, in particular when they are not being used. It has been proposed to fold away their plates (and therefore their wheels) by means of a rotational movement in a vertical direction. It has also been proposed to add to the transport trolley a mechanism for converting the inclination of its first load support means into a rotational movement of its wheels by means of a simplified crossed axis gear system and/or a system which is functionally equivalent to the preceding, for instance a ramp type or connecting bar type system. A shopping cart has also been proposed, specifically in U.S. Pat. No. 6,386,558, in which the load support means are arranged in the form of a fixed frame and the plate (and therefore the wheels) can be folded away horizontally under the frame. A shopping cart has also been proposed, specifically in JP Pat. No. 52119662U, in which the upper part of the legs is removable and the legs can pivot laterally once the upper part has been removed, and in which the load support means are arranged in the form of a frame which can be folded away against the legs and on which the plates are mounted in rotation (and therefore the wheels) so that the latter can be folded away in the frame.
These trolleys are not entirely satisfactory because once folded they occupy a relatively large space and/or they require several manual operations for folding, and because in any case they cannot be folded when carrying a load, and in general once folded they cannot be used for supporting a load.